MOMBASA, Kenya (Reuters) - A Kenyan mob armed with clubs, spears and bows and arrows killed a prominent Scottish gemstone expert during a dispute over mining in a national park, police in the east African country said on Wednesday 12 August.

Campbell Bridges, a 71-year-old internationally-renowned geologist and gemmologist, died late on Tuesday 11 August near the town of Voi in southern Kenya, where he owned several gemstone mines.

John Ole Shampiro, commanding officer of the local Taita Police Division, said Bridges was attacked by a mob of about 20 people armed with crude weapons as he drove his pick-up truck.

"According to witnesses, a group of about 20 people ... used a knife to stab the deceased. We believe, according to our investigations, that his death was a result of a mining dispute involving the deceased and the locals," he told Reuters.

Shampiro said Bridges' son Bruce and four Kenyan employees were with him in the vehicle, but that none of them were hurt.

Bridges' body was flown to the capital Nairobi, he said, and police were searching the area where the incident took place.

Bridges is credited with discovering the green tsavorite gemstone in the late 1960s in the bushland on the nearby border with neighboring Tanzania, according to the New York-based International Colored Gemstone Association (ICA).

Tsavorite is a mineral belonging to the colorful gemstone group of the garnets, the ICA says.

He was also a pioneer in helping introduce the deep-blue gemstone tanzanite to the international jewelry market, said Pavel Sokolov, the ICA's representative to Russia.

"He was a king for us. He was a legend among gemmologists and geologists," Sokolov, president of Sokolov Co., a leading Russian gemstone company, told Reuters by telephone.

"He was very famous among gemmologists. The jewelry market is not so open, but he was open with everybody."

A British Foreign Office spokeswoman in London confirmed Bridges died on Tuesday 11 August from injuries sustained in an attack.

"As his immediate next of kin is American, the U.S. officials are providing consular assistance. We are in close contact with them and offering our full support," she said.

"But as the deceased is a British national, British consular officials are leading the liaison with local authorities, who have confirmed that an investigation is under way," she said, adding that it was inappropriate to comment further for now.

Coast Province police chief Leo Nyongesa had earlier said that detectives were hunting one suspect who was known to them.

(By Celestine Achieng. Additional reporting by David Brough and Peter Griffiths in London; Writing by Daniel Wallis; Editing by Sophie Hares)